
public class ActionTest {
    public static void main(String[] args) {
        //接口不能实例化对象
        //IAction iA=new IAction() ;
        //接口引用指向实现类对象
        IAction iA=new ActionImpl();
        iA.start();
        iA.end();
        System.out.println(IAction.NUM);
        System.out.println(IAction.NUM2);

    }
}
